File download via HTTP or HTTPS

[apacheman7]

We are using Oracle's Portal with Apache server. Whenever we create a link to a .xls or .pdf file for example, the download time seems to take forever. As a comparision, if I were to map to the remote drive and double-click on the .xls file, the file will open in approximately 3-4 secs. However, when I try to open the same file via HTTP, it takes approximately 45-60 secs. Even doing a right-click and Save As on the link takes 45-60 secs. The file is a 15mb .xls file. We've tried it with and without Oracle's webcache enabled.

Is there anything the speed up this process?

Thanks.